I have used the code below to produce a table, however, it does not look correct. The regions that are causing issue are circled in red. Are the multicolumn/multirow packages not working in sync with tabular? Any suggestions to fix these issues?
Thanks in advance!
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{boldline}
\begin{table}[b!]
\caption{.}
\renewcommand{\arraystretch}{1.15}%
\centering
\setlength{\tabcolsep}{5.45pt}
\begin{tabular}{l c || c c c | c c c | c c} %
\hlineB{2}
\multirow{3}{}{} & \multirow{3}{}{Year} & \multicolumn{3}{c|}{Technique} & \multicolumn{3}{c|}{Type} & \multicolumn{2}{c}{Detail}\
& & \multirow{2}{}{Type} &$\tau$ & \multirow{2}{}{Idea} & \multicolumn{3}{c|}{$\bar{u}$} & \multicolumn{2}{c}{Idea}\
& & & [$-$] & & $a$ & $b$ & $c$ & 1 & 2 \ \hline \hline
& 2020 & -- & -- & -- & -- & -- & -- & -- & -- \
\hlineB{2}
\end{tabular}
\end{table}
\end{document}
Since the answers refer to the original code of this question, it is provided here for reference. The above code has been edited by the OP.
\documentclass{article}
\usepackage[utf8]{inputenc}
\begin{document}
\begin{table}[b!]
\caption{.}
\renewcommand{\arraystretch}{1.15}
\centering
\setlength{\tabcolsep}{5.45pt}
\begin{tabular}{l c || c c c | c c c | c c}
\toprule
\multirow{3}{}{} & \multirow{3}{}{Year} & \multicolumn{3}{c}{Technique} & \multicolumn{3}{c}{Type} & \multicolumn{2}{c}{Detail}\
& & \multirow{2}{}{Type} &$\tau$ & \multirow{2}{}{Idea} & \multicolumn{3}{c}{$\bar{u}$} & \multicolumn{2}{c}{Idea}\
& & & [$-$] & & $a$ & $b$ & $c$ & 1 & 2 \ \hline \hline
& 2020 & -- & -- & -- & -- & -- & -- & -- & -- \
\bottomrule
\end{tabular}
\end{table}
\end{document}




\toprulesuggests that you are loadingbooktabs, andbooktabssimply does not like vertical rules, see Vertical table lines are discontinuous with booktabs. – campa Apr 09 '21 at 15:50